Before computers, numerical analyses, particularly financial ones, were usually prepared on an accountant's columnar pad or spreadsheet, with pencil and calculator in hand. By organizing data into columns and rows, spreadsheets afford the rapid assimilation of information by a reader. The task of preparing a spreadsheet on paper, however, is not quite so fast. Instead, the process tends to be very slow, as each entry must be tediously calculated and entered into the spreadsheet. Since all calculations are the responsibility of the preparer, manually prepared spreadsheets are also prone to errors. Hence, preparation of spreadsheets by hand is slow, tedious, and unreliable.
With the advent of microcomputers, a solution was forthcoming in the form of “electronic spreadsheets.” Better known simply as “spreadsheets,” these software programs provide a computerized replacement for the traditional financial modelling tools: the accountant's columnar pad, pencil, and calculator. In some regards, spreadsheet programs are to those tools what word processors are to typewriters. Spreadsheets offer dramatic improvements in ease of creating, editing, and using financial models.
A typical spreadsheet program configures the memory of a computer to resemble the column/row or grid format of an accountant's columnar pad, thus providing a visible calculator for a user. Because this “pad” exists dynamically in the computer's memory, however, it differs from paper pads in several important ways. Locations in the electronic spreadsheet, for example, must be communicated to the computer in a format which it can understand. A common scheme for accomplishing this is to assign a number to each row in a spreadsheet, and a letter to each column. To reference a location at column A and row 1 (i.e., the upper-left hand corner), for example, the user types in “A1”. In this manner, the spreadsheet defines an addressable storage location or “cell” at each intersection of a row with a column.
Data entry into an electronic spreadsheet occurs in much the same manner that information would be entered on an accountant's pad. After a screen cursor is positioned at a desired location, the user can enter alphanumeric information. Besides holding text and numeric information, however, spreadsheet cells can store special instructions or “formulas” specifying calculations to be performed on the numbers stored in spreadsheet cells. In this fashion, cell references can serve as variables in an equation, thereby allowing precise mathematical relationships to be defined between cells. The structure and operation of a spreadsheet program, including advanced functions such as functions and macros, are documented in the technical, trade, and patent literature. For an overview, see e.g., Cobb, S., Using Quattro Pro 2, Borland-OsbomelMcGraw-MII, 1990; and LeBlond, G. and Cobb, D., Using 1-2-3, Que corp., 1985. The disclosures of each of the foregoing are hereby incorporated by reference.
Electronic spreadsheets offer many advantages over their paper counterparts. For one, electronic spreadsheets are much larger (i.e., hold more information) than their paper counterparts; electronic spreadsheets having thousands or even millions of cells are not uncommon. Spreadsheet programs also allow users to perform “what-if” scenarios. After a set of computational relationships has been entered into a worksheet, thanks to imbedded formulas and/or built-in functions for instance, the spread of information can be recalculated using different sets of assumptions, with the results of each recalculation appearing almost instantaneously. Performing this operation manually, with paper and pencil, would require recalculating every relationship in the model with each change made. Thus, electronic spreadsheet systems were invented to solve “what-if” problems, that is, changing an input and seeing what happens to an output.
As exposed above, one essential value of an electronic spreadsheet is to organize data into columns and rows, while automating tedious calculations. A typical, common, and valuable example of such a set of data organized into columns and rows is a range of cells. Even if a range of cells receives a formal and strict definition within electronic spreadsheet environments, it is flexible enough so that information can be included in either a single range of cells or in a set of several ranges of cells. Ranges of cells therefore are quite useful objects. A range of cell can be defined and processed as a whole entity. For example it can be copied from one place to another place within the spreadsheet or from one spreadsheet file to another spreadsheet file.
Ranges of cells are widely used in applications developed in the field of electronic spreadsheets. Most often, the ranges of cells are arranged according to some kind of structure, thus becoming structured ranges of cells. The contents of each cell is defined within an element, where an element is defined as a row of a structured range of cells, and then the same kind of element is repeated a certain number of times, to store/process a variable number of information pieces. Most of the time, several instances of similar structured ranges of cells are used. In the current context where no other tool is really available, instances of such similar structured ranges of cells are frequently created through cut/copy and paste operations.
Creating a new instance of a structured range of cells is complex and lengthy, particularly because a conventional range of cells shows strong limitations:                (i) structure information (such as number of columns, number of rows), format information (such as font style, color or border), and contents information (such as formulas or raw- or informative-data) are mixed,        (ii) the size of the range of cell is fixed at a given instant.        
Therefore, when a spreadsheet user wants to create another range of cells with an identical structure, he/she needs to perform successively several operations. He/she needs to:    1. copy-paste an existing structured range of cells,    2. distinguish between areas containing raw- or informative-data and areas containing generic content such as formulas,    3. empty the copied structured range of cells of the copied raw data while trying to keep the structure, format and generic contents,    4. adjust the size of the structured copied range of cells to his new needs.    5. eventually, fill the raw data area with default values, in order to ease subsequent data entry.
Furthermore, before copying and pasting a structured range of cells, the user must prepare the place for the copied structured range of cells, with the risk of overwriting, and therefore loosing the preexisting information at the destination location. This chain of operations rapidly becomes tedious, lengthy and prone to error, especially when manipulated structured ranges of cells increase in size and complexity.
Updating a structured range of cells is also very often complex, lengthy and prone to error. Such updates include additions of new elements and modifications of existing elements. Several types of modifications can be performed without any specific problem in an electronic spreadsheet environment. However, this is not the case for some modifications, for instance for insertions.
For example, if a row is added by means of a conventional function such as the spreadsheet row insertion method, the created row will be empty. This means that the value for every cell of every element needs to be entered. Entering data or executing copy/paste operations represents an important workload for the user, while the content of each element is known to a certain extent, and should follow the general structure of the structured range of cells. Moreover, normal spreadsheet functions such as the row insertion function may jeopardize the contents of some neighbour elements. A good exemple of an insertion jeopardising neighbour elements is the insertion of a row in a range of cells in which, on every row, a cell such as C17 or more generally (Cn), is pointing to a cell in the previous row, through a formula such as C16+B17, or more generally (Cn−1)+(Bn). After row insertion between rows 16 and 17, the formula in cell C18 becomes C16+B18 instead of the generic formula C17+B18, or more generally after row insertion between rows (n−1) and (n), the formula in cell (Cn+1) becomes (Cn−1)+(Bn+1) instead of the generic formula (Cn)+(Bn+1).
As a second exemple, there are cases where modifications must be done consistently throughout the structured range of cells. Today, this can only be done using specific copy-paste operations applied to the exact area to be modified. This may prove to be very difficult, especially when manipulated structured ranges of cells increase in size and complexity.
Deleting an element of a structured range of cells is an operation prone to error. As a matter of fact, normal spreadsheet functions such as the row deletion function may jeopardize the contents of some neighbour elements, leading to unresolved references (#REF results) or, even worse to wrong formulas that may be difficult to identify. Solving this problem requires additional “context intelligence”, taking into account the structure of the structured range of cells in which the element deletion occurs. Another need appears at the time the user invokes the conventional Delete function after selection in the spreadsheet of one or a plurality of cells. If the selection belongs to a structured range of cells, calling the Delete function by means of a menu or by pressing the “Delete” key, leaves room to ambiguity as to what the user wants to perform. Removing this ambiguity can only be done today by selecting the exact area to be deleted, which may prove to be very difficult, especially as manipulated structured ranges of cells increase in size and complexity. Solving this problem requires additional “context intelligence” to detect this situation, take advantage of the structure of the structured range of cells and offer the relevant choice to the user.
The amount of storage that is necessary to save a structured range of cells may become prohibitive when such a structured range of cells grows in size. On another hand, an important portion of each element of such a structured range of cells may be constituted of OUT fields containing formulas, without any user provided data. Those fields are similar from element to element, and comprise redundant information. This information is not redundant from an end user standpoint, since it is certainly useful, but is redundant because it can be recreated from the base structure of the structured range of cells. Storing and/or conveying this redundant information is a waste that could be avoided if a mechanism would allow to only store/convey the informative data and the information related to the base structure of the structured range of cells.
Sorting data within a selected range of cells introduces the risk of jeopardizing any neighbouring structured range of cells. This risk exists because the selected range of cells is sorted, regardless of the existence of any neighbouring structured range of cells and regardless of the respective positions of the selected range of cells versus any neighbouring structured range of cells. The risk can be avoided only by a careful and precise selection of the range to sort. This selection is prone to error, especially when structured ranges of cells grow in size and complexity. Improved control over sort operations are possible by taking into account the structure and the position of the structured ranges of cells.
The U.S. Pat. No. 5,033,009 is an interesting piece of prior art, that develops the concepts of pattern data and variable data that may be integrated to generate a worksheet file through a worksheet file generator.
This invention however shows many limitations preventing it from solving the set of issues presented here above and, in particular:                It aims at producing a new output spreadsheet from a set of two input files, while there is a need, within a user application environment, to create and manipulate new entities within an existing electronic spreadsheet file, that the user is familiar with.        It contains no mechanism allowing the direct update of the output spreadsheet, other than the regular spreadsheet tool.        It contains no capability to manipulate within the same spreadsheet file, a variable number of different structures and a variable number of instances of each of those structure. The granularity is limited to the spreadsheet file, while the required granularity is that of a structured range of cells.        The so called “file format specification” really mixes structure information (such as number and relative position of columns and rows), presentation information (such as font, color, background, etc.), contents information (such as formulas, etc.).        